ViewPager（视图滑动切换工具）

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example2.viewpager.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpage1"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content" />

</android.support.constraint.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/layout_id1"
    android:background="@color/colorAccent"
    tools:context="com.example2.viewpager.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="layout111111"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/layout_id2"
    android:background="@color/colorPrimary"
    tools:context="com.example2.viewpager.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="layout22222222"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

package com.example2.viewpager;

import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ArrayList<View> listView;
    View view1,view2, view3;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LayoutInflater LI = LayoutInflater.from(this);
        view1 = LI.inflate(R.layout.layout1, null);
        view2 = LI.inflate(R.layout.layout2, null);
        view3 = LI.inflate(R.layout.layout3, null);

        listView = new ArrayList<View>();
        listView.add(view1);
        listView.add(view2);
        listView.add(view3);

        PagerAdapter pageradapter = new PagerAdapter() {
            @Override
            public int getCount() {
                return listView.size();
            }

            @Override
            public boolean isViewFromObject(View view, Object object) {
                return view == object;
            }

            public Object instantiateItem(ViewGroup container, int position){
                container.addView(listView.get(position));
                return listView.get(position);
            }
        };
        Log.e("hj...", "4444444");
        ViewPager viewPager = (ViewPager)findViewById(R.id.viewpage1);
        viewPager.setAdapter(pageradapter);
    }
}